Polyvinylchloride (PVC) is an accepted material for use as tubing in various medical applications and is commonly used as tubing in food processing, particularly for fluids and semi-solids. PVC polymer chains form an attraction to one another, which produces a very rigid plastic. When a soft or flexible plastic is required, a plasticizer may be added to allow the chains to slide against each other. Phthalates may be used as a plasticizer for PVC medical and surgical products, such as a IV tubes, blood bags, and ventilation tubes.
It is believed that phthalate does not bind to the PVC, remaining present as a freely mobile and leachable phase in the plastic. It is also believed that phthalates migrate out of the PVC polymer, since it is not bound to the PVC molecule. When used in medical tubing, phthalate has been found to accumulate in blood, lung, and liver tissue, as well as in fat. These plasticizers may have ill effects on humans, and in particular, children.